Great that you want to stay with Aikido. Are there any fairly highly ranked people who you think could lead the class? If there are such people who don't want to stay with this person, maybe you could start a dojo together? Or if this is not permitted in your organization, you could set up an informal practice. It's too bad so much time has to be wasted in politics, but if you don't feel the current sensei is encouraging to women in general then that is good reason to try to do something else. Other than that of course you could try other Aikido dojos in the area, but if you like what you are currently doing outside of the leadership, then you might want to try to set up your own practice.